1. Technical Field
The present invention relates to a lighting device having a light guide plate and light-emitting elements, a liquid crystal display device having the lighting device, and an electronic apparatus having the liquid crystal display device.
2. Related Art
A liquid crystal display device having a transmissive liquid crystal panel includes a lighting device having a plurality of light-emitting elements arranged along a side end surface of a light guide plate which corresponds to a light incident portion, and the liquid crystal panel is arranged on the side of a light exit surface of the light guide plate so as to be stacked thereon (JP-A-2010-118348, JP-A-2004-165124, JP-A-2009-3081, and JP-A-2011-40388).
In a lighting device disclosed in JP-A-2011-40388 from among JP-A-2010-118348, JP-A-2004-165124, JP-A-2009-3081, and JP-A-2011-40388, light emitting elements are mounted on a first side end surface side of a power source substrate, and the power source substrate is fixed to a frame via screws or the like.
In such a lighting device, for the purpose of enhancing a light outgoing efficiency of illuminating light from the light guide plate and also uniformizing an intensity distribution of the illuminating light, a plurality of diffusing patterns including white dots or grooves are formed on the light guide plate on the light exit surface side or on a surface opposite the light exit surface side in an area overlapping an image display area of a liquid crystal panel. Therefore, the light guide plate is provided with a diffusing area on which the diffusing patterns are formed and an outer edge area arranged between the diffusing area and end portions of the light guide plate, and the diffusing pattern is not formed in the outer edge area.
In contrast, the majority of the light-emitting elements are mounted on the light source substrate at regular intervals. However, portions in which the light-emitting elements are arranged at larger intervals may be formed. For example, when the light source substrate is fixed to the frame with the screws secured between the light-emitting elements, the intervals of the light-emitting elements in areas where the screws are arranged are larger than other portions. When a plurality of light source substrates are arranged, the intervals of the light-emitting elements are larger between adjacent light source substrates than in other portions. Consequently, at a time point when light emitted from the light-emitting elements enters the diffusing area on the light guide plate, the portions in which the intervals of the light-emitting elements are large become discontinuous portions having a light intensity lower than in portions peripheral thereto, which may disadvantageously deteriorate the intensity distribution of illuminating light. Such a problem is hard to solve even when the density of the diffusing patterns in the diffusing area is adjusted properly.